Pump and rotary construction



Jan. 12, 1965 H. B. SCHULTZ 3,165,072-

PUMP AND ROTARY cous'raucuou Filed Sept. 21, 1961 A28 A22 A60 /42 /24 9o 14 INVENTOR.

HAR QLD B. SCI- UL 7'2.-

ATTORNEY.

United States Patent Olfice 3,165,972 Patented Jan. 12, 1965 3,165,072 PUMP AND ROTARY CGNSTRUCTION Harold B. Schultz, douth Bend, Ind, assignor to The Bendix Corporation, South Bend, Ind, a corporation of Delaware Filed Sept. 21, 1961, Ser. No. 139,712 3 Claims. (Cl. 103-217) The present invention relates to an inexpensivefcombination pump and reservoir constructiomand more par- 12. A corner groove 24 is provided at the outside inter ticularly to a combination positive displacement pump and reservoir for producing small flow rates of a high pressure hydraulic fluid in a closed circuit.

Anobject of the present invention is the provision of a new and improved combination hydraulic pump and reservoir which is simple in its design, rugged in its construction and inexpensive to manufacture.

. A further object of the present invention is the provision of a new and improved pump of the above described type wherein the housing for the pump and reservoir is formed by means of a casting having a generally i cup-shaped cavity therein opening into one side surface of the housing, and which includes a cup-shapedside cover plate which closes off. the pump and reservoir.

A still further object of the present invention is the provision of a newand improved pump of the immediately abovedescribed type wherein the housing includes a shaft receiving opening extending genera-11y parallel to the reservoir cavity, and wherein the cover plate overlies the end of the shaft opening to provide lubrication from the reservoir.

j A still more particular object of the present invention is the provision of a new and improved pump of the immediately above describedtype wherein the open end of the housing. is machined ofi to provide a thrust abutment for the pumps'shaft, and to provide a sealing abutment arrangement for the cover plate.

Still another object of the present invention is the provision of a new and improved combination pump and reservoir construction of the above described type wherein the side cover plate acts as a retainer for the pumps shaft. 1

The invention resides in certain constructions and combinations and arrangements of parts; and further objects and advantages will become apparent to those skilled in the art from thefollowing description of the preferred embodiment described with reference to the accompanying drawing forming a part of the specification, and in which: v 1

, FIGURE 1 isa side elevational viewof a combination hydraulic pump and reservoir with its end cover plate removed and a section broken away to show the internal workings of the pump; V

. FIGURE 2 isa crosssectional view of the complete pumpincluding the cover plate taken approximately on the line.22 of FIGURE 1; and

FIGURE 3 is a diametric view ofthe purnp shaft, pump pin 'and interconnecting structure;

p The combination pump v and reservoir shown in the drawing is intended to be used in the closedhydraulic circuit shown in my 'copending application Serial No. 135,489 filed September 1, 1961 now U. S. Paten t No. 3,074,383. As such the pump is intended to provide a discharge pressure from between 1400 to 1800 p.s.i. The housing of the combination pump and reservoir shown inthe drawing is formed by means of a' single generally shallow cup-shaped casting 10 which is closed oifby means of an end cover plate 12. The lower end of the casting 10 has a shaft opening 14 extendingthrough the casting between its opposite closed and open end sides, and the reservoir cavity 16 is cast above and around the boss portion 18 through which the shaft opening 14 i i section of the cylindrical flange 20 and the finish machine end surface 21 to receive a ring seal 28 which effectively seals off the side surface of the casting 10. The end cover plate 12 may be held in place in any suitable manner, and as shownv in the drawing is secured by means of a single machine screw 30 which is suitably threaded into an integrally formed boss 32 which projects out of the closed end 34 of the casting 10 and is machined off flush with the finished machineend surface 21 of the pump. The cover plate 12 bears against the end of the boss 32 and a suitable seal 36 is positioned in a groove 38 in the end of the boss 32 to suitablyseal off the opening through the cover plate 12.

As previously mentioned, the pump is intended to be used in a closed hydraulic circuit and in order that the circulating fluid may be continuously filtered, a short annular partition 40 extends about the integral boss 32 and is finish machined off as at 42 to sealingly abut the bottom annular end of a donut shaped filter 44. Filter 44 is held down upon the annular end surface 42 by means of a cup-shaped washer 46-the outer flange of which engages the top surface of the filter 44, and the inner end of which has an opening through which;the A suitable annular seal 48 is positioned in the bottom of the cup-shaped washer 46, and the cupshaped washer is held down into sealing engagement with the top surface of the filter 44 by means of a coil spring 50 interpositioned between the cover plate 12 and the seal 48. The return fluid is conducted to'the central opening 52 of the filter through a return connection 54 whichis pressed into an opening 56 communicating with the insidesurfaceof the short partition 40 through a fillet of metal 58 cast integrally with the bottom end wall 34 of the housing 10. Return fluid therefore flows into the moon shaped opening 60 formed inwardly of the short partition 40 to flow up into the central opening 52 of the filter, from whence it flows outwardly through the filter structure extends. )il from-.the reservoir cavity .16 is materialvto reach the, reservoir cavity surrounding the filter. By means of this arrangement all hydraulic fluid reaching the portion of the cavityin which the moving pump parts are located is suitably filtered; and a remov able'filler cap 62 is provided in the top surfaceof the pump casting 10' to permit a suitable level to be maintained.

The pumping mechanism shown in'the drawing is of a positive displacement reciprocating type that is driven off of a shaft 64 suitably journalled in the shaft openmg 14 by means of sleeve bearings 66 and 68 that are positioned on opposite sides of a centrally located eccentric portionill of the shaft; The drivepor-tion of the shaft, 1 extends outwardly of the closed end of the casting 10 to. i receive a suitable driving pulley'not shown and which is The shaft opening 14in the boss 13 which surrounds the eccentric portion '70 of the shaft is suitably enlarged or machined. out to receive the reciprocating structure of the pump as connected thereto in a well known manner.

will later be explained. The enlarged section 72 is cornmunicated with the reservoir .cavity'16 by means of a 1 therefore always in communication with the reciprocating structure and the center portion of the shaft 64. Shaft piston member 106.

opening 14 adjacent the outer end of the shaft 64 is suitably enlarged or counterbored as at 76 to receive an oil slipper seal 78, and a short drilled passage 8% communicates the reservoir chamber 16 at the base of the counterbore 76 and thereby lubricates the outer end of the shaft d. I 1

A suitable thrustbearing may beprovided for the shaft 64 in any number of ways, and is most conveniently provided by causing the inner end of the shaft 64 to project out of the machined end surface 26 of the pump toreceive a thrust washer 32 which is integrally connected to the shaft 64 and bears against. the finished machine surface 26. As shown in the drawing; the inner end of the shaft 64- is provided with an annular extension as which extends out through the central opening of the washer S2 and is peened over to affix the washer to the shaft. Inward movement of the shaft 64 is conveniently restrained by means of a ball bearing 86 that is positioned in a drilled socket 88 in the inner end'of the shaft 6 3 in such manner that the ball 86 'projects o'ut of the shaft to be engaged by the cover plate 12. The cover plate 12 may be made in any suitable manner, and asshown in the drawing is formed by means of a sheet metal stamping which has sufiicient flexibility to yieldingly provide a hold-down forceof a desired intensity. Cover plate 12 is dished outwardly-in the region surrounding the machine screw 39 and overlying the end of the shaft 64, so that the ball bearing 86' and thrust washer 82 i's bathed in the filtered oil of the reservoir cavity 16.

The reciprocating pump structure is generally housed .within a cylindrical boss 90 formed as an integral part in the bottomof the casting it) opposite the central opening 74- -leading to the eccentric-portion 7d of the shaft 64. The cylindrical boss $8 is provided with a central opening 92 therethrough which is in line with the opening 74 in the boss 13, and which is counterbored as at 94 to receive astack-up of machined elements which together form :the pumping structure of the unit; The fluid pressurizing cylinder chamber of the pump structure is formed by means of a flanged body 96 having an inwardly proje'cting portion'98 that is provided with an accurately di- "mensioned axiallyextending opening 1% therethrough. The ilange. portioriltll bf the body )6 is seated up against a the shoulder' lll provided by the counterbore $4, and the central opening 134) slidably receives an accuratelyground cylindrical piston member 1436 which is adapted to reciprocate in'the opening 1043. The outer end of the opening body'96'with a suitable seal 1E6 positioned therebetween to seal off the outer endof the counterbore M28. The

inner end of. the. cup-shaped portion abuts theshoulder 118' formed by the reduced diameter section 112 to bias the-flange 96'into engagement with the inner shoulder 104. A suitable coil spring 120 is positioned between the bottom of the counterbore 103' and the check valve 113 tobias' the checkvalve Ill} into sealing engagement with the bottom surface of the cup-shaped portion of the port- Ting hold down member 114. Suitable drilled passageways 122 and124 are provided through the sides of the boss 93) and porting member 114 to communicate with an axially extending passageway 126'which extends through the holddown member to communicatefiuid' from the reservoir :16 to the surface of the inlet check valve lit The bottom surface or" thecup-shaped portion which is engaged by the inlet check valve-110 forms an inlet valve 7 seat-for closing ofi the inlet passages 122 and 126 from the counterbore 168 duringthedischarge stroke of the An unloading pin 128 is slidingly received in the outer end of the axial passageway 126, for reasons which will later be explained; and the inner portion of the opening 126 between the passageway 124 and the inlet check valve 11th is slightly enlarged to provide a free passage of fluid around the outside of pin 12%. The outer end of the porting and holddown member lid is provided with a machined annular fiat face 13%, and an axially outwardly extending boss 132 through which the opening 12s extends. The periphery of the suction poppet I is serrated to permit passage of fluid around its outside edges, and a diagonal discharge passage 134 is provided in the porting member to communicate discharge from the counterbore 1&8 to the center of the annular machined surface 139 adjacent one side of the axial boss 32. A discharge poppet 136 having a molded rubber seal 138 on its outer periphery is positioned for sealing engagement with the machine surface 13% in the region surrounding the di agonal opening 1% to prevent the return of fiuid through the diagonal discharge passage 134. The discharge pop= pet 133 is biased into sealing engagement with the machine surface 13% by means of a coil spring l4l-which in turn is held in position by means of an annular plastic hold down member 142 that is positioned around the boss 13?..- The plastic holddown member 142 has a cylindrical opening 144 for receiving and guiding the poppet 136, and further includes a small discharge passage 14-6 in its outer face to permit passage or fluid to the outer end of the opening 94 in the boss 96.

The outer end of the opening 94 is closed off by a threaded cup-shaped cap 148 which effects a suitable seal with respect to the sidewalls of the bore 94 and sandwiches the holddown members 142, porting member 114 and flange 162 of the cylinder body Q6 between the inner shoulder MP4 of the housing and the threaded end cap 148. The internal cavity of the cup-shaped end cap 148 receives the outer end of the unloading pin 12%, which is biased outwardly by means of a coil spring 150 that is positioned between a suitable inner spring retainer 152 that abuts the end of the boss 132 and an outer spring retainer 154 suitably aifixed to the outer end of the unloading pin 128. A suitable seal is provided between the pin 12% and the outer end of the boss 132. The spring 151} normally holds the outer spring retainer 154 into abutment with the bottom of the cup-shaped opening in the threaded cap 148 until sufficient discharge pressure is received from the discharge opening 146 to produce a differential pressure across the opposite ends of the unloading pin 128 to overcome the force of the spring and move the pin inwardly to unseat the suction poppet 110 from its seating surface. Unloading pin 12% and coil spring 150 thereby provide a simple arrangement for unseating the suction poppet Hill at a predetermined discharge pressure and thereby unload the pump. The threaded cap 14% further includes a conventional outlet connection 156 by means of which it can be suitably connected to the hydraulic distribution system.

The piston pin W6 is caused to be reciprocated by means of the eccentric portion 7% of the shaft 64 through a connecting arm arrangement which is extremely simple and which automatically locks and. holds the parts together. This connecting arm structure comprises an abutment link Edi which has an inner end shaped to COD. form to the eccentric shaft portion 76, and which extends through the opening 74 to receive the inner end of the piston pin member 106, The abutment link 166 has a cylindrical opening 162 spaced slightly inwardly from its outer end and extending transversely through the abutment link 16%. The outer end of the abutment link inner end of the piston member 106 extends through slot 164 and is received in a short bore 166 of approximately the same size as the pin 1% and which extends only part Ways through a cylindrical wrist pin 168 that is positioned J t in the opening 162. The side surfaces of the Slot 164 prevent lateral movement of the abutment link 160 relative to the piston 106; and the piston 106 in turn holds the wrist pin 168 within the abutment link 160. Withdrawal of the inner end of the pin 106 out of the connecting arm structure is prevented by means of a piston return spring 170 positioned between the bottom of the cylinder body 96 and a spring retainer 172 which is suitably afllxed to the piston pin 106. Piston return spring 170 is strong enough, and serves the additional function, to at all times biasingthe inner end of the connecting or abutment link 160 against the eccentric surface 70 of the shaft 64 so that no additional holddown structure need be provided. It will be noted that the pumps reciprocating structure is assured of complete and proper lubrication, inasmuch as the reciprocating structure is positioned within the portion of the reservoir chamber 16 which at all times has filtered hydraulic oil contained therein. The reciprocating parts above described are completely open to view when the end cover plate 12 of the structure is removed, and further are readily accessible during assembly.

As previously mentioned, the pump and reservoir construction shown in the drawing is intended to be used in a closed hydraulic circuit wherein return flow enters the inlet connection 54 to flow through the moon shaped opening 60 in the bottomof the reservoir cavity, through the central opening of the filter 44, and out into the reservoir chamber 16. As previously mentioned, the center section of the shaft 64, as well as the portions on the outside of its bearings 66 and 68, are open to the reservoir chamber 16 so that complete lubrication is always assurred. The shaft 64 may be rotated in any suitable manner, as for example by means of a V-belt pulley so that its eccentrically located center portion 70 forces the connecting link 160 towards the pump structure in the boss 90 to cause the piston pin 106 to displace fluid from its receiving bore 100. The outward stroke of the pin 106 displaces fluid from the counterbore 108 out through the discharge passage 134, to lift poppet member 136 out of engagement with its seating surface 130 and thereby flow to the discharge connection 156.

After the eccentric 70 reaches top dead center, the

spring 170 biases the piston pin 106, wrist pin 168, and

connecting link 160 inwardly with sufficient force to hold the connecting link 160 against the eccentric portion 70 of the shaft 64. This causes the piston pin 106 to be re tracted in its receiving bore 100 and thereby draw fluid from the reservoir chamber 16 through the passages 122, 124, and 126 past the intake valve 110 and into the counterbore 103. The next 180 cycle of the shaft 64 thereafter produces a discharge stroke to repeat the cycle.

When the pressure in the outlet connection 156 reaches a predetermined value, say 1400 psi. suflicient diiferential pressure across the unloading pin 128 exists to overcome the force of the coil spring 150 and force the pin 128 inwardly by an amount which lifts the inlet check valve 110 out of engagement with its seating surface and thereby unload the pump. As long as this predetermined pressure exists in the outlet connection 156, the inlet check valve 110 remains out of engagement with its seating surface so that the reciprocation of the piston pin 106 alternately sucks anddischarges fluid to the reservoir 16 without building up pressure and without absorbing any ap-.

preciable amount of energy from the shaft 64.

It will be apparent that the objects heretofore enumerated as well as others have been accomplished; and that there has been provided a pumping structure, as well-as a combination pump and reservoir construction-which is extremely simple in design, rugged in construction and inexpensive to manufacture.

' l While the invention has been described in considerable detail, I do not wish to be limited to the particular. conhaving a thrust washer bearing against said machined open i end and said first boss portion, an; annular recessma- 6 rangements thereof which come within the practice of those skilled in the art to which the invention relates.

I claim:

l. A pump construction comprising: a generally horizonal cylindrically shaped housing having an internal cup-shaped reservoir cavity opening into one end surface of said housing, the open end and closed end of said housing forming the opposite sides of said pump construction, said housing including an integral boss portion extending between said ends adjacent the lower side of said housing, a shaft receiving opening in said boss pontion extending between said ends of said housing, a shaft journalled in said opening and projecting from said closed end of said housing, said housing having a generally cylindrically shaped sidewall surrounding said reservoir cavity and said shaft, an annular recess machined in the outside surface of said cylindrical sidewall adjacent said open end, a cupshaped cover plate with its bottom covering said open end and its sidewall extending over said recess in said cylindrical wall, said cover plate being dished outwardly to form a lubricant passage a' seal positioned between said sidewall of said cover plate and said recess, pump means driven by said shaft and opening into said cavity to be immersed in its fluid and receive suction therefrom, and a ball thrust bearing positioned between said shaft and said cover plate such that said ball thrust bearing is in to said lubricant passage.

2. A pump construction comprising: a generally horizontal cylindrically shaped housing having an internal cup-shaped reservoir cavity opening into one end surface of said housing, the open end and closed end of said housing forming the opposite sides of said pump construction, said housing including a first integral boss portion extending between said ends adjacent the lower side of said housing, a shaft receiving opening in said boss portion extending between said ends of said housing, a.

shaft journalled in said opening and projecting from said closed end of said housing, said housing having a generally cylindrically shaped sidewall surrounding said reservoir cavity and said shaft, said shaft having a flange bearing against said boss portion of said housing, an annular recess machined in the outside surface of said cylindrical sidewall, a cup-shaped cover plate with its bottom covering said open end and its sidewall extending over said recess, said cover plate being dished outwardly to form a radial lubricant passage terminating outwardly adjacent said sidewall of said housing where it underlies said bottom of said cover plate, a seal positioned between said sidewall of said cover and said recess, pump means driven by said shaft and opening into said cavity to be immersed in its fluid and receive suction thereform, and a ball thrust bearing positioned between said shaft and said cover plate in said lubricant passage.

3. A pump construction comprising: a generally horizontal cylindrically shaped housing having an internal cup-shaped reservoir cavity opening into one end surface of said housing, the open end and closed end of said housing forming the opposite sides of said pump construction, said housing including a first integral boss portion extending between said ends adjacent the lower side of said housing, a shaft journaled in said opening and portion extending between said open and closed ends of said housing, a shaft journalled in said opening and projecting from the closed end of said housing, said housing having a generally cylindrically shaped sidewall surrounding said reservoir cavity and said shaft, said housing having a second integral boss portion extending between said open and closed ends and located generally centrally of said sidewall, said open endof. said housing being finish machined across the'end' of said sidewall and said first and second integral boss portions, said shaft chimed in the juncture of said. outside surface of said cylindrical sidewall and said machined end surface, a

E cup-shaped cover plate with its bottom covering said open end. and its sidewall extending over said recess, a seal positioned between said sidewall of said coverand said recess, said cover plate being formed with a passage extending between said second boss portion and said housing sidewall to overlie said first boss portion pump means driven by said shaft and opening into said cavity to be immersed in its fiuid and receive suction therefrom, a ball thrust bearing positioned between said shaft and said cover platesinsaid passage, an annular filter surrounding said second integral boss portion and sealed with respect to said, bottom closed end of said cavity, means sealing thetop of said annular filter to said second integral portion, a return connection communicating with the central opening of said annular filter and a'rneans communicating said' passage with saidfilter to provide a contaminant free lubricant for said ball thrust bearing and said thrust washer.

References Cited in the file of this patent UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,165,072 January 12, 1965 Harold B. Schultz It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 61, strike out "journaled in said opening and" and insert instead receiving opening in said first boss Signed and sealed this 22nd day of June 1965,

(SEAL) Attest:

ERNEST W. SWIDER' EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A PUMP CONSTRUCTION COMPRISING: A GENERALLY HORIZONAL CYLINDRICALLY SHAPED HOUSING AN INTERNAL CUP-SHAPED RESERVOIR CAVITY OPENING INTO ONE ENE SURFACE OF SAID HOUSING, THE OPEN AND CLOSED END OF SAID HOUSING FORMING THE OPPOSITE SIDE OF SAID PUMP CONSTRUCTION, SAID HOUSING INCLUDING AN INTEGRAL BOSS PORTION EXTENDING BETWEEN SAID ENDS ADJACENT THE LOWER SIDE OF SAID HOUSING, A SHAFT RECEIVING OPENING IN SAID BOSS PORTION EXTENDING BETWEEN SAID ENDS OF SAID HOUSING, A SHAFT JOURNALLED IN SAID OPENING AND PORJECTING FROM SAID CLOSED END OF SAID HOUSING, SAID HOUSING HAVING A GENERALLY CYLINDRICALLY SHAPED SIDEWALL SURROUNDING SAID RESERVOIR CAVITY AND SAID SHAFT, AN ANNULAR RECESS MACHINED IN THE OUTSIDE SURFACE OF SAID CYLINDRICAL SIDEWALLY ADJACENT SAID OPEN END, A CUPSHAPED COVER PLATE WITH ITS BOTTOM COVERING SAID OPEN END AND ITS SIDEWALL EXTENDING OVER SAID RECESS IN SAID CYLINDRICAL WALL, SAID COVER PLATE BEING DISHED OUTWARDLY TO FORM A LUBRICANT PASSAGE A SEAL POSITION BETWEEN SAID SIDEWALL OF SAID COVER PLATE AND SAID RECESS, PUMP MEANS DRIVEN BY SAID SHAFT AND OPENING INTO SAID CAVITY TO BE IMMERSED IN ITS FLUID AND RECEIVE SUCTION THEREFROM, AND A BALL THRUST BEARING POSITIONED BETWEEN SAID SHAFT AND SAID COVER PLATE SUCH THAT SAID BALL THRUST BEARING IS IN TO SAID LUBRICANT PASSAGE. 